The opening of Mercedes-Benz Stadium will mark a rite of passage not just for the Falcons or Blank, but for Atlanta itself. NFL stadiums—new NFL stadiums, that is, with gleaming features and staggering budgets—have become the sine qua non for the cities that claim a franchise. Want to host a Super Bowl? Build a new stadium. Want to ensure your home team doesn’t decamp to another city? Build a new stadium.